Is it by any chance a timing issue? I've situations where the empty tabs are not shown after restarting DO from the ground.
OTH, I've (most) situations where I get empty tabs right after the restart.
Most of the time, I see a slight delay before DO shows the main window in those situations.
Some, if not all tabs in tab groups, that are empty, point to network shares. Maybe this explains the short delay when starting DO.
But I get empty tabs with local drives, too, so basically not the best explanation for the issue.